Thermostat



May 21, 1935. .1. M. JOHNSON THERMOSTAT Filed Dec. '7, 1935 0 John M d o /7175a? BY m I g-g INVENT Y VIII/g! ATTORNEY u; N. F E? .F UT IF 0 5 & \Iw I g imam A w 3% L! m: w LT n H m N 1F, 3 a

Patented May 21, 1935 PATENT OFFICE THERMOSTAT John M. Johnson, Kansas City, Mo.

Application December 7, 1933, Serial No. 701,312

8 Claims.

My invention relates to thermostats and more particularly to a thermostat adapted to be placed in a pair of main line wires used in connection with a fire alarm system.

It has been the current practice in installing thermostats to be used with fire alarm systems to place the thermostats upon the ceiling of a room to be protected by means of screws, bolts,

' or the like, and make the electrical connections to the thermostats after they have been placed. This involves considerable labor and, in the event the protection is no longer desired, it is difiicult to remove the thermostats without defacing the ceiling.

One object of my invention is to provide a thermostat which may be readily installed in a simple and expeditious manner.

' Another object of my invention is to provide a line of thermostats which may be assembled at a factory and taken to the place of installation in assembled condition.

Another object of my invention is to provide a novel arrangement for assembling a line of thermostats.

A further object of my invention is to provide a simple and efiicient thermostat for breaking a circuit or circuits in event of fire.

Other and further objects of my invention will appear from the following description.

In the accompanying drawing which forms part of the instant invention and is to be read in conjunction therewith and in which like numerals are used in the various views to indicate like parts;

Figure 1 is a perspective view of a room fitted with the thermostats of my invention.

Figure 2 is an elevation of a thermostat embodying one mode of carrying out my invention.

Figure 3 is a sectional view taken on a line 3--3 of Figure 2.

Figure 4 is a sectional view of the thermostat after it has been released by heat.

Figure 5 is a sectional view taken on a line 5-5 of Figure 4.

Figure 6 is a sectional view of the means for placing the line of thermostats under tension.

Figure 7 is an enlarged fragmentary sectional View showing details of construction.

In general, my invention contemplates the provision of a pair of body members having conductors clamped thereto in contact with a pair of conducting members which are joined to each other by means of fusible alloy. Normally, the circuit is completed through the conducting members. The thermostats in the line are placed under tension. When the fusible alloy is melted by heat, the connections through the line are broken, operating a fire alarm. Novel means are provided for securing the main line wires to the thermostat.

More particularly referring now to the drawing, the thermostat comprises a pair of body members I, externally screw threaded at 2 and provided with bores in which conducting members 3 and 4 are secured in any suitable manner. The conducting members 3 and 4 normally overlap each other as shown in Figure 2. They are secured in this position by means of a fusible alloy. A pair of annular clamping members 5 are provided. Each clamping member 5 is internally threaded and adapted to be screwed over the body member as can readily be seen by reference to Figure 4. A washer 6 is provided, having a pair of holes through which the conductors are adapted to pass. The holes in the washer 5 are out of alignment with the bore openings of the body member I. A ferrule I is fitted over each conductor to prevent its being sheared.

By referring to Figures 4 and 7, it will be clearly seen that a conductor 8 entering through the bore 9 of the clamping member 5 passesthrough a hole of the washer 6 and terminates in a bore of the body member I in electrical contact with a conducting member 4. Due to the fact that the holes in the washer are out of alignment with the bore openings a clamping action is achieved. The ferrule I being rounded prevents the conductors from being sheared if too great pressure is exerted in screwing clamping member 5 over the external screw threads 2 of the body member I. In assembling a line of thermostats, the ends of the conductors are prepared and inserted in assembled relation as shown in Figure 4. The clamping members 5 are then screwed to clamp the conductors in position. The body members I are joined by means of spring l0 so that the loose ends of the line will not drop when the thermostat is operated by a fire. The conductors 8 pass through a clamping jaw II as shown in Figure 6. A tapered, screw threaded nut i2 is adapted to be screwed over threaded clamping member II to grip the conductors tightly. A spring [4 is secured to the nut l2 in any suitable manner. The other end of the spring 14 is provided with a hook-like member IS. A pair of clamping members such as shown in Figure 6 are secured to the conductors 8 at each end of the room to be protected. The hook I5 is secured to the walls, it being understood, of course, that the clamping members are positioned so that the springs M will be in tension. This can be readily appreciated by reference to Figure l. The result will be that the entire line, comprising conductors 8 and thermostats, will be under tension.

In operation, the line of thermostats assembled for the particular space to be conditioned, is mounted as shown in Figure 1. Suitable supports I6 may be provided at intervals to prevent the line from sagging. In the event of fire at any portion of the room,'the melting of the fusible alloy l1 holding respective conducting members 3 and 4 together, and the tension of springs I4 will cause the thermostats to assume the position shown in Figure 4, insuring the breaking of both circuits.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. A thermostat comprising in combination a body member, a pair of conducting members carried thereby, means for connecting a pair of conductors to said conducting members, a second body member, a second pair of conducting members carried thereby, means for connecting a second pair of conductors to said second conducting members, fusible alloy holding the respective first and second conducting members together and means for placing said alloy under tension.

2. A pair of conducting Wires having interposed therein a plurality of thermostats each comprising separable members, fusible alloy holding the separable members in electrical contact to complete the circuit through each of the wires and common means for placing said wires and separable members under tension.

'3. A thermostat including in combination a pair of body members, a pair of conducting members carried by each of the body members, fusible alloy joining respective conducting members, said body members being provided with screw threads, threaded clamping members provided with bores adapted tocoact with said body members to clamp conductors in electrical contact with said conducting members.

4. A pair of conducting wires" having interposed therein a thermostat having a pair of body members, a pair of conducting members carried by each of the body members, fusible alloy joining respective conducting members, said body members being provided with screw threads, threaded clamping members provided with bores through which the conducting wires are adapted to pass, said threaded clamping members adapted to coact with said body members to clamp the conducting wires in electrical contact with said conducting members, and means for placing said wires under tension.

5. A line of thermostats comprising a pair of conductors, means for clamping said conductors to a thermostat, a second pair of conductors, means for clamping said conductors to said thermostat, a second thermostat, means for clamping said second thermostat to said second conductors, a third pair of conductors, means for clamping said third conductors to said second thermostat, each of said thermostats having a pair of conducting bridges separable by heat, the electrical connections being such that a pair of main line wires having a plurality of thermostats interposed therein results, and means for placing the line under physical tension.

6. A thermostat comprising in combination a pair of body members each havinga pair of bores, conducting means secured in each of said bores, fusible means joining respective conducting means, said body members being externally threaded, a pair of clamping members provided with internally threaded bores adapted to be screwed over said body members, and a conductor in each of the bores of said body members clamped in electrical contact with said conducting means by said clamping members.

7. A thermostat including a pair of members joined by fusible means each of said members comprising a body member, a pair of bores in said body member, conducting means disposed in said bores, said body member being externally threaded, an internally threaded annular clamping member screwed over said body member, a washer within said clamping member, said washer being provided with a pair of holes out of alignment with'the bores of said body member, and a pair of conductors passing through said clamping means and terminating in said bores and clamped in electrical contact with said conducting means.

8. A line of thermostats comprising in combination a plurality of thermostats electrically connected in series, each of said thermostats including separable conductors, fusible alloy completing the circuit through said separable conductors and means for placing the line under physical tension.

- JOHN M. JOHNSON. 

